Relationship Between African-American Race and Delirium in the ICU

Objectives: Delirium is a highly prevalent syndrome of acute brain dysfunction among critically ill patients that has been linked to multiple risk factors, such as age, preexisting cognitive impairment, and use of sedatives; but to date, the relationship between race and delirium is unclear. We conducted this study to identify whether African-American race is a risk factor for developing ICU delirium. Design: A prospective cohort study. Setting: Medical and surgical ICUs of a university-affiliated, safety net hospital in Indianapolis, IN. Patients: A total of 2,087 consecutive admissions with 1,008 African Americans admitted to the ICU services from May 2009 to August 2012. Interventions: None. Measurements and Main Results: Incident delirium was defined as first positive Confusion Assessment Method for the ICU result after an initial negative Confusion Assessment Method for the ICU; and prevalent delirium was defined as positive Confusion Assessment Method for the ICU on first Confusion Assessment Method for the ICU assessment. The overall incident delirium rate in African Americans was 8.7% compared with 10.4% in Caucasians (p = 0.26). The prevalent delirium rate was 14% in both African Americans and Caucasians (p = 0.95). Significant age and race interactions were detected for incident delirium (p = 0.02) but not for prevalent delirium (p = 0.3). The hazard ratio for incident delirium for African Americans in the 18-49 years age group compared with Caucasians of similar age was 0.4 (0.1-0.9). The hazard and odds ratios for incident and prevalent delirium in other groups were not different. Conclusions: African-American race does not confer any additional risk for developing incident or prevalent delirium in the ICU. Instead, younger African Americans tend to have lower rates of incident delirium compared with Caucasians of similar age.